The invention relates to a spring system having a double rolling-lobe flexible member especially for use in the forward wheel fork of a two-wheel vehicle.
U.S. Pat. No. 6,375,170 discloses a spring system having a double rolling-lobe flexible member. Such a spring system is made up of two air spring elements mounted as mirror images to each other. Each of the two spring elements comprises essentially a flexible member and a roll-off piston. A cover plate, which is required by a conventional air spring, can be omitted because a support unit (support bell, outer jacket) is provided for laterally delimiting the flexible members. In a preferred embodiment, the two flexible members define a single piece, that is, the two flexible members define a double rolling-lobe flexible member. The roll-off pistons are slightly conical at their ends and the outer jacket is configured to be slightly conical at both ends.
In a deflection operation, one part of the double rolling-lobe flexible member is compressed with the aid of the one roll-off piston, while, at the same time, the other part of the double rolling-lobe flexible member is relieved of load with the aid of the other roll-off piston. Because of the conicality of the outer jacket and roll-off pistons, there results an upper/lower asymmetry which has the consequence that the effective diameters of the two rolling lobes change from which a soft spring action results.
In the known spring system, the outer jacket is manufactured as a single piece. In the manufacture of the spring system, difficulties can occur because of the conically tapered ends of the outer jacket. A further unsolved problem lies in a reliable fixation of the double rolling-lobe flexible member on the outer jacket.
It is an object of the invention to provide a reliable positioning and fixing of the double rolling-lobe flexible member on the outer jacket and to furthermore provide a practical assembly of the air spring parts and especially of the outer jacket.
The spring arrangement of the invention includes: first and second spring components coaxially mounted in opposition to each other; the first spring component including a first rolling-lobe flexible member and a first roll-off piston; the second spring component including a second rolling-lobe flexible member and a second roll-off piston; the first and second rolling-lobe flexible members conjointly defining a common rolling-lobe flexible member having an interior; an outer jacket including first and second parts corresponding to the first and second spring components; the first and second parts having respective ends conjointly defining a common interface; the common rolling-lobe flexible member having a clamp ring arranged in the interior; and, the clamp ring being disposed between the ends with a portion of the flexible member being clamped between the ends and the clamp ring at the interface whereby a slippage of the flexible member relative to the outer jacket is prevented.
According to a feature of the invention, a clamp ring is mounted within the double rolling-lobe flexible member and is clamped between the ends of the two-part outer jacket. In this way, the double rolling-lobe flexible member is reliably fixed at the pregiven location. The double rolling-lobe flexible member is clamped between the clamp ring disposed internally and the outer jacket ends disposed externally. A slippage of the flexible member along the inner wall of the outer jacket is thereby prevented. The cover plates which are otherwise needed for the force transmission, especially in simple rolling-lobe flexible members, can be entirely omitted here. A further advantage of the two-part outer jacket is in the easy assembly of the spring system. Roll-off pistons and rolling-lobe flexible members need not be introduced via the conically tapered ends of a one-piece outer jacket. In lieu thereof, the assembly takes place via the relatively wide mutually facing ends of the outer jacket parts according to the invention.
With the use of a clamp nut, a releasable connection of the two outer jacket parts is obtained. In this way, the spring system can be disassembled and reassembled without difficulty.
A cost effective and nonetheless reliable fixation of the rolling-lobe flexible member at the outer jacket can be provided by means of a flanging procedure.
The clamp ring is preferably a flat ring. In lieu of a flat ring, also a flexible inner ring can be introduced into the pressureless flexible member to facilitate assembly.